پیشرفت های اخیر در زمینه تحقیق و توسعه در کاهش فعالیت فریتی / مارتنزیتی فولاد

Several types of reduced activation ferritic/martensitic (RAFM) steel have been developed over the past 30 years in China, Europe, India, Japan, Russia and the USA for application in ITER test blanket modules (TBMs) and future fusion DEMO and power reactors. The progress has been particularly important during the past few years with evaluation of mechanical properties of these steels before and after irradiation and in contact with different cooling media. This paper presents recent RAFM steel results obtained in ITER partner countries in relation to different TBM and DEMO options.

Reduced activation ferritic/martensitic (RAFM) steel is considered the reference structural material for future fusion power reactors, due to its technological maturity, i.e. advanced fabrication routes, welding technology and general industrial experience [1] and [2]. It is also chosen as the main structural material for most ITER test blanket modules (TBMs), which are under development by ITER participants. Hence, RAFM steels are being widely developed in Europe, Japan, Russia, China, the USA and India. Specifically, F82H is being developed by the Japan Atomic Energy Agency (JAEA), JLF-1 by Japanese universities and the National Institute for Fusion Science (NIFS), Eurofer97 is being developed in Europe within the framework of the European Fusion Development Agreement (EFDA) program and Fusion for Energy (F4E) program, China low activation martensitic (CLAM) steel is being developed by the Institute of Nuclear Energy Safety Technology (INEST), Chinese Academy of Sciences (CAS) and 9Cr-2WVTa is being developed by Oak Ridge National Laboratory (ORNL). The specific chemical compositions of the RAFM steels are listed in Table 1[1], [2], [3] and [4]. Recent progress has mainly focused on fabrication techniques, mechanical properties, manufacturing of TBMs, the effects of neutron irradiation, compatibility experiments and development of coatings. These are presented in detail in the following sections.

Great progress has been made on RAFM steel development, e.g. large-scale fabrication, mechanical properties testing before and after neutron irradiation, fabrication of TBM, etc. For applications in DEMO and fusion reactors, more efforts are still needed in the following aspects: (1) Studies on the helium and hydrogen synergetic effect with displacement damage and the effects of other transmutation products on properties of RAFMs, especially by using IFMIF (International fusion Materials Irradiation Facility) or small fusion reactors in the future. (2) Development of inspection methods of diffusion welds for TBM components with flow channels, welding techniques for difficult-to-reach positions, and fabrication of tritium permeation barriers.